Eric I carry the knife a lot....gun shows, Militaria shows, and around the house on weekends etc., and yes it does spend a weekend in the sheath. But this knife has been stored in a knife box for many years now when I don’t carry it. The verdigris has probably been on the knife for a while and yes I need to clean it off. It just needs a good cleaning.
Mike....my patina comment was a joke. I know what verdigris is.
Bottom line, this knife has not been stored in the sheath.